COMPARISON OF THREE PROTOCOLS FOR TIGHT GLYCEMIC CONTROL IN CARDIAC SURGERY PATIENTS

Abstract

Objective: We performed a randomized trial to compare three insulin-titration protocols for tight glycemic control (TGC) in surgical ICU: an absolute glucose (Matias) protocol, a relative glucose change (Bath) protocol, and an enhanced model predictive control algorithm (eMPC).

Research Design and Methods: 120 consecutive post-cardiac surgery patients were randomized to the three protocols with a target glycemia range from 4.4 to 6.1 mmol/l. Intravenous insulin was administered continuously or in combination with insulin boluses (Matias protocol). Blood glucose was measured in 1-4 hour intervals as requested by protocols.

Results: eMPC algorithm gave best performance as assessed by time to target (8.8±2.2 vs. 10.9±1.0 vs. 12.3±1.9 hours; eMPC vs Matias vs Bath; P<0.05), average blood glucose after reaching the target (5.2±0.1 vs. 6.2±0.1 vs. 5.8±0.1 mmol/l; P<0.01), time in target (62.8±4.4 vs. 48.4±3.28 vs. 55.5±3.2 %, P<0.05), time in hyperglycemia >8.3 mmol/l (1.3±1.2 vs.^. 12.8±2.2 vs. 6.5±2.0 %, P<0.05), and sampling interval (2.3±0.1 vs. 2.1±0.1 vs. 1.8±0.1 hours, P <0.05). However, time in hypoglycemia risk range (2.9-4.3 mmol/l) in eMPC group was longest (22.2±1.9 vs. 10.9±1.5 vs. 13.1±1.6; P<0.05). No severe hypoglycemic episode (< 2.3 mmol/l) occurred in eMPC group compared to 1 in Matias and 2 in Bath groups, respectively.

Conclusion: eMPC algorithm provided best TGC without increasing risk of severe hypoglycemia while requiring fewest glucose measurements. Overall, all algorithms were safe and effective in the maintenance of TGC in cardiac surgery patients.